—Can I come to ask for some advice at any time?
— Yes, of course. _______
| A．If you’re convenient. | B．At your convenience. |
| C．Don’t worry. | D．Don’t mention it. |
It took the scientists seven days to________Takla Makan________“the sea of death”.
| A．climb;calling | B．through;called |
| C．across;naming | D．cross;named |
—Where did ________traffic accident happen,sir?
—It took place at ________crossroads by the bank.
| A．a;/ | B．the;a | C．/;a | D．a;a |
__________ the text a second time，the meaning will become clearer to you.
| A．Read | B．Reading | C．If reading | D．When you read |
Information technology is taught in most schools，__________we have entered the information society.
| A．so | B．while | C．still | D．for |
Scientists say it may be five or six years __________it is possible to test this medicine on human patients.
| A．since | B．after | C．before | D．when |